.c-container .conta-left-box .conta-left-middle .course-index .bad-video{
	width: 810px;
	height: 455px;
	background-color: #ccc;
	position: relative;
	overflow: hidden;
}
.c-container .conta-left-box .conta-left-middle .course-index .bad-video video{
    width: 100%;
    height: 100%;
    display: block;
    object-fit:fill;
}